HEAT EXCHANGERS WITH INTEGRALLY FORMED FLOW TURBULATORS

RELATED APPLICATION

[0001] This patent claims the benefit of U.S. Provisional Patent Application No. 63/736,492, which was filed on December 19, 2024. U.S. Provisional Patent Application No. 63/736,492 is hereby incorporated herein by reference in its entirety. Priority to U.S. Provisional Patent Application No. 63/736,492 is hereby claimed.

FIELD OF THE DISCLOSURE

[0002] This disclosure relates generally to heat exchangers and, more particularly, to integrally formed flow turbulators.

BACKGROUND

[0003] Heat exchangers are used in a wide range of applications. Heat exchangers are employed in various types of vehicles including aircraft, spacecraft, watercraft and land-based vehicles. Optimizing the efficiency of heat exchangers is important when reducing costs and improving performance.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004]FIG. 1 is a block diagram of an example cooling system within which the teachings herein may be employed.

[0005]FIG. 2 is a view of an example heat exchanger constructed in accordance with the teachings herein.

[0006]FIG. 3 is a view of a second example heat exchanger constructed in accordance with the teachings herein.

[0007]FIGS. 4A-4C are views of an example fluid passage cross-section of a heat exchanger constructed in accordance with the teachings herein.

[0008] In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. The figures are not necessarily to scale.

SUMMARY

[0009] An example heat exchanger includes a plurality of fluid passages forming a fluid flow path through the heat exchanger and a plurality of flow turbulators within the fluid passages, the flow turbulators within the fluid flow path and integrally formed with a body of the heat exchanger.

[0010] An example cooling system includes a plurality of tubes including a series of straight tubes connected end to end by curved tubes to form a flow path, a plurality of flow turbulators within the plurality of tubes, the flow turbulators being integrally formed within bodies of at least some of the tubes, and a pump to move a heat transfer fluid though the flow path.

[0011] An example method for manufacturing a heat exchanger includes forming a plurality of fluid passages and forming a plurality flow turbulators within the fluid passages by successively depositing and fusing an additive material.

DETAILED DESCRIPTION

[0012] As used herein, the term “heat exchanger” encompasses structures or apparatus that enable the transfer of thermal energy between a medium and an environment. Such a medium, for example, can include a fluid, a solid, or a structure. Such an environment, for example, can include an atmosphere, vacuum, a body of fluid, etc. Heat exchangers are used to cool various systems such as those on automobiles, motorcycles, aircraft, spacecraft, watercraft and other vehicles. When used in a land-based vehicle or aircraft, a heat exchanger typically transfers heat from a heat transfer fluid, which is flowing through the heat exchanger, to air passing through the heat exchanger. At low heat transfer fluid flow, boundary layers develop within the heat exchanger flow passages, which inhibits efficient heat transfer between the fluid and the walls of the fluid flow passages. To reduce or eliminate the development of boundary layers, heat exchanger based cooling systems require heat transfer fluid within the heat exchanger to flow at a rate that is sufficiently high to introduce turbulence in the fluid. This turbulence disrupts the formation of boundary layers and raises the heat transfer coefficient and, thus, the efficiency of the heat exchanger.

[0013] Certain applications require low power fluid pumps that are not capable of a flow rate high enough to create sufficient turbulence in the heat transfer fluid to achieve a sufficiently high heat transfer coefficient. In other applications, a fluid pump may divide flow into a plurality of fluid paths which further results in low flow through an individual passage ultimately resulting in a lower heat transfer coefficient. Flow turbulators are one known approach to increasing turbulence within a heat exchanger at relatively low fluid flow rates. These known flow turbulators are continuous, uniform elongate structures that are cut to length and inserted in the tubes of a heat exchanger. Typically, once inserted, these known flow turbulators extend continuously from an inlet tank to an outlet tank of the heat exchanger to create turbulence and disturb the boundary layer allowing for effective heat transfer at a lower flow rate in the system. However, because these known turbulators extend from the inlet tank to the outlet tank, they can create a substantial flow obstruction and, as a result, a substantial pressure drop from the inlet to the outlet of the heat exchanger. Such a pressure drop can necessitate a higher power pump. In other words, the increased heat transfer coefficient benefit of these known turbulators is offset by the increased pressure drop they generate and, as a result, there may be little to no reduction in the power required for the fluid pump.

[0014] In the aerospace industry, low power pumps are desirable from an efficiency standpoint. Reducing power consumption in a demanding environment such as space allows for longer missions, or for the power to be directed to other equipment on board the spacecraft. The examples disclosed herein allow for the usage of low power pumps by increasing turbulent flow while substantially decreasing the pressure drop from the inlet to the outlet of a heat exchanger as compared to known flow turbulators. The disclosed examples provide for flow turbulators that are integrally formed in the flow passages or tubes of the heat exchanger. Integrally forming the flow turbulators in the flow passages or tubes of the heat exchanger allows for different types (e.g. shapes, sizes, etc.) of flow turbulators to be placed throughout the heat exchanger. For example, a spring type turbulator can be formed in a section of a heat exchanger tube, while a ball type turbulator can be formed in another section of the heat exchanger tube.

[0015] Integrally forming flow turbulators in the tubes of a heat exchanger enables heat exchangers to be optimized for specific applications. Different sized heat exchangers may benefit from certain types of flow turbulators in different sections of the heat exchanger. Integrally formed flow turbulators also allow flow turbulators to be placed in curved sections of the heat exchanger tubing, which is not possible with known solutions due to the rigidness of known turbulators. For example, twisted wall turbulators are not capable of being pushed through bends of a heat exchanger tube. Spring type turbulators may be pushed through a large radius bend of a heat exchanger tube due to their elasticity. However, spring turbulators cannot be pushed through the relatively small radius bends that are typically found in heat exchangers.

[0016]FIG. 1. is a view of an example cooling system 100 including an example heat exchanger 101, a pump 102, a cold plate 103, and a plurality of tubes 104 fluidly interconnecting the heat exchanger 101, the pump 102, and the cold plate 103. FIG. 2. is a detailed view of an example heat exchanger 200 that may be used to implement the heat exchanger 101 of FIG. 1. The illustrated example includes a plurality of serially coupled fluid passages (e.g. a series of straight tubes connected end to end by curved tubes) 201 forming a fluid flow path through the heat exchanger 101 extending between an inlet 204 and an outlet 205, and a plurality of flow turbulators 202a, 202b, 202c within the fluid passages 201. In some examples, there may be two or more sets of serially coupled fluid passages 201 extending between an inlet 204 and an outlet 205 forming a parallel flow path within the heat exchanger 101. In the illustrated example, the fluid passages 201 form a serpentine flow path. In some examples, the fluid passages 201 may form a non-serpentine fluid flow path such as a straight flow path. The flow turbulators 202a, 202b, 202c are disposed within the fluid flow path and are integrally formed with a body of the heat exchanger 101. In the illustrated example, there are five discrete sections 203 of integrally formed flow turbulators 202a, 202b, 202c equally spaced throughout the flow path. In some examples, the heat exchanger 101 may include other numbers of discrete sections of flow turbulators 203 (e.g. 1, 2, 3, 6, etc.). Integrally formed flow turbulators may be formed with different manufacturing methods, including additive manufacturing. Different additive manufacturing methods could include selective laser melting, powder bed laser melting, selective laser sintering, laser directed energy deposition, electrochemical additive manufacturing, etc. In one example, additive manufacturing of the heat exchanger 101 could include forming a plurality of fluid passages by successively depositing and fusing an additive material and forming a plurality of flow turbulators within the fluid passages by successively depositing and fusing an additive material. In the illustrated example, the heat exchanger 101 includes multiple types of flow turbulators 202a, 202b, 202c.

[0017] The integrally formed flow turbulators 202a, 202b, 202c allow the heat exchanger to be optimized for specific applications. Spiral wall turbulator 202a has a generally spiral or helical shape along the fluid passage wall. As fluid flows through the spiral wall turbulator 202a, the fluid is forced to follow a swirling path which disrupts the boundary layer that forms near the fluid passage wall. Rib type turbulator 202b includes raised elements or protrusions on the fluid passage wall that can be arranged in various patterns and have different shapes. As fluid flows through the flow passages the ribs create obstacles that disrupt the boundary layer that forms near the fluid passage wall. Spring type turbulator 202c includes a helically coiled spring usually in contact with the fluid passage wall that disrupts the boundary layer that forms at or on the fluid passage wall. Certain types of flow turbulators 202a, 202b, 202c such as the spring 202c, rib 202b, spiral wall 202a, and ball type turbulators may be beneficial in certain sections of the heat exchanger 101. Further, the illustrated example includes sections with flow turbulators 202a, 202b, 202c and sections without flow turbulators. The integrally formed flow turbulators 202a, 202b, 202c allow for discrete flow turbulator sections and sections without flow turbulators to be strategically placed throughout the heat exchanger 101, which allows for optimization of pressure drop across the inlet 204 and the outlet 205.

[0018]FIG. 3. is another example heat exchanger 300 that may be used to implement the heat exchanger 101 of FIG. 1. The example heat exchanger 300 includes a series of straight tubes 301 connected end to end by curved tubes 302 to form a flow path, and a plurality of flow turbulators 303a, 303b, 303c within the tubes 301, 302, the flow turbulators 303a, 303b, 303c being integrally formed within bodies of the tubes 301, 302. In the illustrated example, the flow path is a serpentine pattern. In some examples, the fluid path may form a non-serpentine pattern such as a straight flow path. In some examples, the series of straight tubes 301 may be connected by curved tubes with sharp angles (e.g. ninety degrees). The illustrated example includes five unequally spaced discrete flow turbulator sections 304. Integrally forming the flow turbulators 303a, 303b, 303c into the tubes 301, 302 allows for the placement of discrete flow turbulator sections 304 throughout the tubes 301, 302, including the curved sections 302. In the illustrated example, the flow turbulator 303a includes two different variations of rib flow turbulators in one flow turbulator section 304. One variation includes circular protrusions 305 integrated with the fluid passage walls in line with the tubes 301, 302 while another variation includes a zig-zag pattern protrusion 306 integrated with the fluid passage walls. In other examples, discrete flow turbulator sections 304 can include different types of flow turbulators (e.g. spring 303b, rib 303a, spiral wall 303c, ball type, etc.).

[0019]FIG. 4. is a cross-sectional view of the fluid passages of heat exchanger 101 of FIG. 1. In FIG. 4A, the tubes have polygonal cross-section. In FIG. 4B, the tubes have generally circular cross-sections and in FIG. 4C the tubes have elliptical cross-sections. Further, when the tubes include polygonal or elliptical cross-sections an integrally formed flow turbulator can include spring, rib, spiral wall, and ball type turbulators altered to occupy the tubes and create turbulence effectively.

[0020]“Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc., may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended. The term “and/or” when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) B with C, or (7) A with B and with C. As used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities, etc., the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities, etc., the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B.

[0021] As used herein, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude a plurality. The term “a” or “an” object, as used herein, refers to one or more of that object. The terms “a” (or “an”), “one or more”, and “at least one” are used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements, or actions may be implemented by, e.g., the same entity or object.  Additionally, although individual features may be included in different examples or claims, these may possibly be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous. 

[0022] As used herein, unless otherwise stated, the term “above” describes the relationship of two parts relative to Earth. A first part is above a second part, if the second part has at least one part between Earth and the first part. Likewise, as used herein, a first part is “below” a second part when the first part is closer to the Earth than the second part. As noted above, a first part can be above or below a second part with one or more of: other parts therebetween, without other parts therebetween, with the first and second parts touching, or without the first and second parts being in direct contact with one another.

[0023]As used in this patent, stating that any part (e.g., a layer, film, area, region, or plate) is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween.

[0024] As used herein, connection references (e.g., attached, coupled, connected, and joined) may include intermediate members between the elements referenced by the connection reference and/or relative movement between those elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and/or in fixed relation to each other. As used herein, stating that any part is in “contact” with another part is defined to mean that there is no intermediate part between the two parts.

[0025] Unless specifically stated otherwise, descriptors such as “first,” “second,” “third,” etc., are used herein without imputing or otherwise indicating any meaning of priority, physical order, arrangement in a list, and/or ordering in any way, but are merely used as labels and/or arbitrary names to distinguish elements for ease of understanding the disclosed examples. In some examples, the descriptor “first” may be used to refer to an element in the detailed description, while the same element may be referred to in a claim with a different descriptor such as “second” or “third.” In such instances, it should be understood that such descriptors are used merely for identifying those elements distinctly within the context of the discussion (e.g., within a claim) in which the elements might, for example, otherwise share a same name.

[0026]From the foregoing, it will be appreciated that example systems, apparatus, articles of manufacture, and methods have been disclosed that enable heat exchangers with integrally formed discrete flow turbulator sections and sections devoid of flow turbulators. Disclosed systems, apparatus, articles of manufacture, and methods are accordingly directed to one or more improvement(s) in the operation of a machine such as a computer or other electronic and/or mechanical device.

[0027] The following claims are hereby incorporated into this Detailed Description by this reference. Although certain example systems, apparatus, articles of manufacture, and methods have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all systems, apparatus, articles of manufacture, and methods fairly falling within the scope of the claims of this patent.

[0028] Example methods, apparatus, systems, and articles of manufacture to enable heat exchangers with integrally formed discrete flow turbulator sections and sections devoid of flow turbulators are disclosed herein. Further examples and combinations thereof include the following.

[0029]Example 1 includes a heat exchanger including a plurality of fluid passages forming a fluid flow path through the heat exchanger, and a plurality of flow turbulators within the fluid passages, the flow turbulators within the fluid flow path and integrally formed with a body of the heat exchanger.

[0030]Example 2 includes the heat exchanger of example 1, wherein the flow turbulators are disposed in discrete sections of the fluid flow path.

[0031]Example 3 includes the heat exchanger of example 1, wherein the flow turbulators are unequally spaced along the flow path.

[0032]Example 4 includes the heat exchanger of example 1, wherein at least some of the flow turbulators have different dimensions than other ones of the flow turbulators.

[0033]Example 5 includes the heat exchanger of example 1, wherein discrete portions of the flow path are devoid of the turbulators.

[0034]Example 6 includes the heat exchanger of example 1, wherein the fluid passages have a polygonal cross-sectional shape.

[0035]Example 7 includes the heat exchanger of example 1, wherein the fluid passages have an elliptical cross-sectional shape.

[0036]Example 8 includes the heat exchanger of example 1, wherein the flow turbulators include spiral shaped walls.

[0037]Example 9 includes the heat exchanger of example 1, wherein the flow turbulators include ribs.

[0038]Example 10 includes a cooling system including a plurality of tubes including a series of straight tubes connected end to end by curved tubes to form a flow path, a plurality of flow turbulators within the plurality of tubes, the flow turbulators being integrally formed within bodies of at least some of the plurality of tubes, and a pump to move a heat transfer fluid through the flow path.

[0039]Example 11 includes the cooling system of example 10, wherein the flow turbulators are disposed in some of the plurality of tubes and are absent from other ones of the plurality of tubes.

[0040]Example 12 includes the cooling system of example 10, wherein the flow turbulators are unequally spaced along the flow path.

[0041]Example 13 includes the cooling system of example 10, wherein at least one of the flow turbulators has different dimensions or shape than other ones of the flow turbulators.

[0042]Example 14 includes the cooling system of example 10, wherein discrete portions of the flow path are devoid of the turbulators.

[0043]Example 15 includes the cooling system of example 10, wherein the plurality of tubes have a polygonal cross-sectional shape.

[0044]Example 16 includes the cooling system of example 10, wherein the plurality of tubes have an elliptical cross-sectional shape.

[0045]Example 17 includes the cooling system of example 10, wherein the flow turbulators include spiral shaped walls.

[0046]Example 18 includes the cooling system of example 10, wherein the flow turbulator includes ribs.

[0047]Example 19 includes a method for manufacturing a heat exchanger including forming a plurality of fluid and forming a plurality of flow turbulators within the fluid passages by successively depositing and fusing an additive material.

[0048]Example 20 includes the method of example 19, wherein forming the flow turbulators includes using selective laser sintering, powder bed laser melting, or electrochemical additive manufacturing.